To determine the number of moles of hydrogen gas contained in 21.3 liters at STP (Standard Temperature and Pressure), follow these steps:
### Step-by-step Solution
1. Understand the relationship between volume and moles at STP:
At Standard Temperature and Pressure, 1 mole of any ideal gas occupies 22.4 liters.
2. Given Data:
The volume of hydrogen gas we have is 21.3 liters.
3. Formula:
To find the number of moles \(\( n \)\), we use the formula:
\(\[
n = \frac{V}{V_m}
\]\)
where \(\( V \)\) is the volume of the gas, and \(\( V_m \)\) is the molar volume of the gas at STP (22.4 liters/mole).
4. Substitute the values:
\(\[
n = \frac{21.3 \, \text{liters}}{22.4 \, \text{liters/mole}}
\]\)
5. Calculate the number of moles:
\(\[
n \approx 0.9508928571428572 \, \text{moles}
\]\)
### Final Answer:
Thus, the number of moles of hydrogen gas contained in 21.3 liters at STP is approximately \(\( 0.9509 \)\) moles.
